Thermal control system of the unpressurized instrument compartment for Intergeliozond spacecraft intended for solar research at close distances

Consideration is given to specifics of thermal control of the unpressurized instrument compartment of the Intergeliozond spacecraft developed by Lavochkin Association by the order of Roscosmos State Corporation. Brief description of the spacecraft and relevant bibliographic references are given. Two identical spacecraft will be developed under the Intergeliozond program, which will perform physical research of the Sun at close distances operating in heliocentric non-ecliptic orbits. Taking into account the conditions of the spacecraft operation characterized by a significant hange of the incoming solar radiation density, a pumped fluid loop-based segment is proposed to be introduced in addition to the existing basic TCS based on heat pipes and honeycomb panels. The pumped fluid loop fulfills the function of a general-purpose system, which ensures temperature conditions in the ground developmental test phases, and during the flight operation, and is capable of ensuring a heat supply or additional cooling of the instrument compartment. A multiple-option process characterized by a level of complexity of the fluid loop integration into TCS of the instrument compartment of the spacecraft is presented.